A spring manufacturing apparatus that processes a wire into a spring comprises a wire sending unit that sends out a wire and a tool disposed at an exit of the wire sending unit and processing the wire. When a coil spring is manufactured, a wire touches the tool (bending die) and a coil part is formed. On the coil spring, an appurtenant part is formed in addition to the coil part.
The appurtenant part is formed, for example, by bending the wire connecting with the end part of the coil part. One of the tools is a spindle that bends the wire. The spindle comprises a cylinder that is rotatable about the axis, a pivot provided at the center of an end surface of the cylinder, and a protruding part protruding from the end surface in a position away from the pivot.
In the spring manufacturing machine, the wire is engaged between the pivot and the protruding part, and the cylinder is rotated around the pivot to press the protruding part against the wire. The wire bends along the outer peripheral surface of the pivot.
The bending form of the bent part depends on the curvature of the outer surface of the pivot. For this reason, when a plurality of parts of the wire are bent in different bending forms, it is necessary to stop the processing once and change the spindle to another one having a pivot with a different curvature.
To avoid the change to another spindle, it is necessary that the spring manufacturing machine comprises a plurality of spindles in advance; however, the number of processing tools that can be attached to the frame of the spring manufacturing machine is limited and when the number of spindles is increased, it is necessary to detach other processing tool such as the bending die.
An example embodiment is made in view of such circumstances, and an object thereof is to provide a wire bending device and a spring manufacturing machine that are capable of bending a wire in a desired bending form without the need to change the spindle or increase the number of spindles.
A bending device according to the example embodiment comprises a processing part having two protruding parts that protrude from an end surface of a pillar part and that bend a wire, wherein at least one of the protruding parts has a curved surface part, and the wire is disposed between the two protruding parts, the pillar part is rotated around an axis of the pillar part to bend the wire along the curved surface part, the bending device comprises plural processing parts, curvature of the curved surface part of the protruding part in each processing part are different, and the bending device further comprises: a rotary part that supports the processing parts and rotates about an axis intersecting the length direction of the pillar part; an accommodating part that is cylindrical and accommodates the rotary part at an end part of the accommodating part so as to be rotatable; and a mechanism that rotates the accommodating part about an axis of the accommodating part.
In the bending device according to the example embodiment, the plural processing parts are installed next to each other around a rotation axis of the rotary part.
The bending device according to the example embodiment comprises: a cylindrical housing that supports the accommodating part so as to be rotatable about an axis of the accommodating part; and a tool attachment part that is provided on an end part of the housing and that a tool to processes the wire is attached to.
The bending device according to the example embodiment comprises a mechanism that moves the accommodating part in a direction in which the wire is supplied or in a direction intersecting the direction.
A spring manufacturing machine according to the example embodiment comprises: the bending device according to any of the above-described bending devices; a support wall that supports the bending device at one side and has an opening, wherein the wire is sent out from another side to the one side of the support wall through the opening.
In the example embodiment, the curvatures of the curved surface parts of a plurality of protruding parts are made different. The processing parts having the protruding parts are supported by the rotary part, and the rotary part is rotated to select one of the processing parts. By rotating the cylindrical accommodating part about the axis thereof, the wire is bent along the curved surface part of the selected protruding part.